This invention relates to signal distribution systems, and more particularly to a system for communicating data for control of individual loads in a system.
In commercial buildings or other facilities, lighting, heating, ventilating, air-conditioning and other loads can be controlled according to requirements determined by computer so as to optimize energy usage. A significantly greater overall reduction in energy usage may thereby be achieved, provided that control can be extended, individually, to a large number of separate loads so as to achieve a much finer control mesh than provided by present control systems. In general, the larger the building, the greater the potential for energy savings. Moreover, computer determination of optimum load controls is important if it is desired to eliminate the need to have these load controls manipulated manually several times each day at a plurality of remote locations.
Control signals generated by a microcomputer may be distributed to each switched fixture load in the system by transmission through the power distribution circuits (which are typically A.C.) in the facility or, in the alternative, through a communication circuit within the facility, on a frequency modulated carrier. If necessary, a separate microcomputer may be employed for each of the lighting, heating, ventilating, air-conditioning and other systems in the building. The microcomputer may be easily programmed to the requirements of each separate system of fixtures in the building, and provides an economical means of storing, in semiconductor memory, information on desired states of a large number of individually switched devices within the system. If several systems are employed in a single building or other facility, overall control of the systems may be accomplished by a master microcomputer or by a central process control computer.
Accordingly, one object of the invention is to provide a method and apparatus for generating redundant address and function codes for transmission to a plurality of receiving stations.
Another object is to provide a method and apparatus for transmitting function data over power distribution or communication circuits to selected receiving stations.
Another object is to provide a system for transmitting control signals, generated at any of a plurality of receiving stations, back to a central control location over power distribution or communication circuits for purposes of controlling a pre-programmed combination of loads.